[7] Troubleshooting of each part
(1) LEV
1) Overview of LEV operation
LEV (electronic expansion valve) receives pulse signals from the outdoor-side controller board and drives a valve
by means of a servomotor.
The valve opening angle changes in proportion to the number of pulses.
<Outdoor-side controller board and LEV>
<Pulse signal output and valve operation>
The output pulses change in the following order:
Valve closing
1
→
2
→
3
→
4
→
1
Valve opening
4
→
3
→
2
→
1
→
4
*1. When the LEV opening angle is not changed, all output
phases turn OFF.
2. When the output misses a phase or remains ON, the mo-
tor cannot rotate smoothly and makes a clacking sound
and vibrates.
White Red Orange
Blue
Brown
Yellow
Brown
Red
Blue
Yellow
White
Connector
Outdoor-side controller board CN40
Drive circuit
Output (phase)
No.
ø1
ø2
ø3
ø4
Output state
1
2
3
4
ON
OFF
OFF
ON
ON
ON
OFF
OFF
OFF
ON
ON
OFF
OFF
OFF
ON
ON
LEV opening and closing operations
*
When the power is turned on, to register the valve posi-
tion, a 2200 pulses valve close signal is output and is al-
ways set to point A .
If the valve moves smoothly, the LEV will not generate a sound
or vibration, but at E
→
A and when the valve is locked, a
sound louder than the sound generated by missing phase,
etc. will be generated.
*
Generation of sound can be checked by placing the tip of
a screwdriver against the valve and your ear against the
handle.
V
alv
e opening
angle
(flo
w)
Valve closing
Valve opening
Increased throttling region (80 - 100 pulses)
Full open
2000 pulses
Pulse count
D
C
A
E
B
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